The U.S. Federal Communications Commission will launch an inquiry into Google Voice, the Web-based voice service, after complaints that the tech giant is blocking some calls.

The FCC action comes after AT&T, in a letter to the agency Sept. 25, complained that Google was pushing for net neutrality rules that would prohibit broadband providers from blocking or slowing Internet traffic while at the same time blocking some calls on its service to some phone numbers with high access charges.

“Numerous press reports indicate that Google is systematically blocking telephone calls from consumers that use Google Voice to call telephone numbers in certain rural communities,” wrote Robert Quinn, AT&T’s senior vice president for federal regulatory affairs. “By blocking these calls, Google is able to reduce its access expenses. Other providers, including those with which Google Voice competes, are banned from call blocking [by the FCC].”

Access charges are fees that telephone carriers exchange with each other for connecting phone calls to their networks. In some rural areas of the U.S., access charges are significantly higher than in other areas.

The FCC sent a letter to Google on Friday asking the company about its Voice service. The letter asks Google how many people have been invited to beta test Google Voice, how Google Voice calls are routed, and if Google blocks calls to some telephone carriers. The letter also asks if Google Voice competes with traditional telecom carriers.

The reasons Google Voice restricts calls to some local phone carriers is “simple,” said Richard Whitt, Google’s Washington, D.C., telecom and media counsel.

“Not only do they charge exorbitant termination rates for calls, but they also partner with adult sex chat lines and ‘free’ conference calling centers to drive high volumes of traffic,” Whitt wrote on the Google public policy blog. “This practice has been called ‘access stimulation’ or ‘traffic pumping’ (clearly by someone with a sense of humor). Google Voice is a free application and we want to keep it that way for all our users—which we could not afford to do if we paid these ludicrously high charges.”

Google Voice is a free Web-based application, and it’s not intended to replace existing phone lines, Whitt added. “The goal of Google Voice is to provide a useful, unified communications tool (including, among others, soldiers and the homeless),” he wrote.

AT&T has also asked the FCC for permission to block calls to the same rural areas, Whitt noted. “Why? For exactly the same reasons we restrict them—the exorbitant termination rates,” he said. “Of course, AT&T charges customers for their services and also receives hundreds of millions of dollars in universal service subsidies.”

The new questions from the FCC came two days after a group of 20 U.S. lawmakers, led by Representative Steve Buyer, an Indiana Republican, sent a letter to the FCC, asking the agency to investigate Google Voice.

Google’s position that it can block calls to some rural carriers is “ill conceived and unfair to rural constituents,” the letter said. “It is our opinion that a company should not be able to evade compliance with important principles of access and competition set forth by the FCC by simply self-declaring it is not subject to them without further investigation.”

Craig Settles , a broadband consultant, called the spat between AT&T and Google “a heavy dose of circus entertainment with a serious issue buried underneath.”

Some rural carriers have complained that AT&T has refused to pay its access charges bills, Settles said.

“AT&T is using Google to create a smoke screen with Congress, the media and the public because the FCC’s push for net neutrality scares the beejeebers out of them,” he added. “What some people aren’t seeing is the underlying fact that both AT&T’s and Google’s treatment of rural communities is exactly why we need net neutrality laws.”

Google correctly claims to not be a telecom carrier, he said. But the company is “nevertheless offering a Web-centered service that is discriminating against rural communities,” he said. “If you offer a calling service, but you prevent people from calling to particular parts of the country, that’s discriminatory. This is why carriers are prevented from doing it.”

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